The Hauts-de-Seine department is home to a concentration of large IT services and consulting firms. These companies, many of which are well-established, offer a range of services from telecommunications to digital transformation. Notable examples include Orange, a global telecommunications operator; ALTEN, providing engineering and IT services; VINCI Energies, which implements multi-technical solutions for environmental transition; and Devoteam, an AI-driven tech consulting firm.
A significant pattern among these companies is their focus on digital transformation and technological solutions across various industries. Many are headquartered in a few key cities within the department, such as Boulogne-Billancourt, Nanterre, and Neuilly-sur-Seine.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Orangeorange.com
A leading global telecommunications operator offering services to millions of customers and multinational companies across 26 countries |
146,935 | |||
| 2 | 38,710 | ||||
| 3 |
VINCI Energiesvinci-energies.com
Contributes to environmental transition by implementing customized multi-technical solutions from design to maintenance, enhancing infrastructure reliability, efficiency, and sustainability for energy and digital sectors. |
25,848 | |||
| 4 |
Altrancapgemini-engineering.com
Altran, now Capgemini Engineering, offers engineering services Follow them on LinkedIn for updates and insights |
11,652 | |||
| 5 |
Devoteamdevoteam.com
AI-driven tech consulting firm specializing in cloud platforms, cyber, data, and sustainability, guiding businesses through sustainable digital transformation to deliver value. |
10,274 | |||
| 6 |
Econocomeconocom.com
Supplies, finances, and provides managed services for workplace, audiovisual, and infrastructures, supporting businesses in their digital transformation with equipment and support. |
7,123 | |||
| 7 |
Actemiumactemium.com
Delivering bespoke solutions and services globally, combining local business unit expertise to create value throughout the industrial life cycle for a sustainable world. |
6,718 | |||
| 8 |
Astekastekgroup.fr
Supports clients with high-value service, deep technical expertise across technology, operations, and engineering, focusing on sustainable digital transformation with humans at the core. |
6,035 | |||
| 9 |
Vulcain Engineering Groupvulcain-eng.com
Provides engineering consulting and project solutions for energy and environmental sectors, delivering technical assistance, expertise, and project management globally. |
5,234 | |||
| 10 |
OPENopen.global
Supports large companies and public organizations in digital transformation, focusing on technological performance, sovereignty, digital sobriety, and scaling innovations with advanced solutions. |
4,705 | |||
| 11 |
Axiansaxians.com
A technology company supporting digital transformation by providing ICT solutions in cybersecurity, telecommunication, data analytics, cloud services, and more |
4,186 | |||
| 12 |
Cegedimcegedim.com
Technology and services for digital data flow management in healthcare ecosystems and B2B, plus business software publishing for healthcare and insurance professionals. |
4,103 | |||
| 13 |
Scalianscalian.com
A global company founded in 1989 with 3 business lines focusing on Digital Transformation, Digital Systems, and Operations Performance across various countries |
4,098 | |||
| 14 | 3,016 | ||||
| 15 |
CS GROUPcs-soprasteria.com
Designs, builds, deploys, and maintains critical systems with innovative solutions and products, ensuring operational efficiency and security for client missions. |
2,968 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
VINCI Energies en France
Accelerating environmental transition in France by focusing on energy and digital transformations for factories, buildings, cities, and energy/transport infrastructure with innovative solutions |
2,953 | |||
| 17 | 2,930 | ||||
| 18 | 2,854 | ||||
| 19 |
Sogetrelsogetrel.fr
A leader in digital transformation, specializing in digital infrastructure services and connected devices to enhance citizens' lives, business performance, and sustainable development |
2,581 | |||
| 20 |
Apsideapside.com
Provides consulting, engineering in Information Systems, Technical and Scientific Computing, Automotive and Financial Engineering, for large French and European groups. |
2,300 | |||
| 21 |
HELPLINEhelpline.fr
Specialized in user support outsourcing, AI-enhanced employee experience, and IT asset management. Supports IT departments and offers seamless employee experience. |
2,115 | |||
| 22 | 2,075 | ||||
| 23 |
Infotelinfotel.com
Provides IT and digital transformation consulting for large enterprises, focusing on strategic design, technological expertise, and agile development, from conception to implementation. |
1,894 | |||
| 24 |
Extiaextia-group.com
Offers IT consulting services across various sectors, focusing on employee well-being to drive project success and client performance with a collaborative approach. |
1,881 | |||
| 25 |
Sopra HR Softwaresoprahr.com
Provides payroll, HR management, and digitalization solutions for medium to large organizations, leveraging digital and AI for HR transformation in local and international contexts. |
1,880 | |||
| 26 |
Davidson consultingdavidson.fr
A management consulting and technology company with over 2,000 employees, expanding internationally with a focus on employee well-being and creativity |
1,843 | |||
| 27 |
Sofrecomsofrecom.com
Advises, guides, and supports telecommunications players' digital transformation and green transition, offering business, network, and IT consulting for improved operational performance. |
1,469 | |||
| 28 | 1,460 | ||||
| 29 |
SCC Francescc.com
Provides comprehensive IT solutions, including cybersecurity, digital workplace, and hybrid infrastructure, enabling businesses to optimize operations and achieve their goals. |
1,422 | |||
| 30 | 1,358 | ||||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.
More company lists in the Hauts-de-Seine department
- The largest companies in the Hauts-de-Seine department 5,160
- Multinational companies in the Hauts-de-Seine department 1,231
- IT Services and IT Consulting companies in the Hauts-de-Seine department 706
- Professional services firms in the Hauts-de-Seine department 629
- Consulting firms in the Hauts-de-Seine department 563
- Companies with in-house R&D in the Hauts-de-Seine department 510
- SaaS companies in the Hauts-de-Seine department 389
- Business Consulting and Services companies in the Hauts-de-Seine department 304
- Software Development companies in the Hauts-de-Seine department 301
- Retail chains in the Hauts-de-Seine department 292
- Manufacturers in the Hauts-de-Seine department 285
- Advertising Services companies in the Hauts-de-Seine department 281
- Marketing and communications agencies in the Hauts-de-Seine department 235
- Subscription businesses in the Hauts-de-Seine department 228
- Hardware manufacturers in the Hauts-de-Seine department 199
- Financial services firms in the Hauts-de-Seine department 198
- Companies with a mobile app in the Hauts-de-Seine department 189
- Critical infrastructure operators in the Hauts-de-Seine department 169
- AI companies in the Hauts-de-Seine department 159
- Education providers in the Hauts-de-Seine department 159
- Cybersecurity companies in the Hauts-de-Seine department 154
- Distributors and wholesalers in the Hauts-de-Seine department 154
- Recruitment and staffing agencies in the Hauts-de-Seine department 152
- Energy companies in the Hauts-de-Seine department 144
The same list elsewhere in France
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- IT services companies in Auvergne-Rh么ne-Alpes 519
- IT services companies in the Rh么ne department 286
- IT services companies in Occitanie 280
- IT services companies in Provence-Alpes-C么te d'Azur 268
- IT services companies in Grand Est 248
- IT services companies in Hauts-de-France 236
- IT services companies in Pays de la Loire 205
- IT services companies in Nouvelle-Aquitaine 194
- IT services companies in the Nord department 170
- IT services companies in the Haute-Garonne department 158
- IT services companies in the Bouches-du-Rh么ne department 155
- IT services companies in the Loire-Atlantique department 130
- IT services companies in the Yvelines department 121
- IT services companies in Brittany 113
- IT services companies in the Val-de-Marne department 101
- IT services companies in the Gironde department 99
- IT services companies in Paris 1,386
- IT services companies in Lyon 171
- IT services companies in Boulogne-Billancourt 125
- IT services companies in Toulouse 119
- IT services companies in Levallois-Perret 94
- IT services companies in Neuilly-sur-Seine 87